A new biochar-regulated catalyst can remove 96.9% of the widely used insecticide imidacloprid from water within 40 minutes, offering a promising route for treating pesticide-contaminated wastewater.
Neonicotinoid insecticides have become an important part of modern agriculture, but their persistence in water has raised growing ecological concerns. Among them, imidacloprid is one of the most widely used and frequently detected compounds. Because it can threaten aquatic invertebrates even at very low concentrations, researchers are looking for faster, more stable, and more selective ways to break it down before it reaches sensitive ecosystems.
In a new study published in Biochar, researchers developed a cobalt manganese spinel catalyst regulated by biochar and derived from layered double hydroxides. The optimized material, named CoMn0.75/BC, activated peroxymonosulfate, a common oxidant used in advanced water treatment, and achieved 96.9% removal of 5 mg L−1 imidacloprid within 40 minutes. Its degradation rate was substantially higher than systems using biochar or cobalt manganese oxide alone.
"Biochar is not only a support material in this system. It actively changes how the catalyst works, steering the reaction toward more selective non-radical oxidation pathways," said the study's corresponding authors. "This provides a useful design strategy for next-generation catalysts used in pesticide wastewater treatment."
Many advanced oxidation processes rely heavily on radical species, which can be powerful but are often sensitive to pH, background ions, and natural organic matter in real water. In contrast, the new CoMn0.75/BC system shifted the reaction toward non-radical pathways dominated by high-valent metal oxo species and singlet oxygen. These species can offer more selective oxidation and better resistance to interference from complex water components.
The research team found that biochar played several connected roles. Its porous structure helped disperse cobalt manganese spinel nanoparticles and prevent aggregation. Its oxygen-containing functional groups, especially carbonyl groups, helped chelate cobalt and manganese ions and stabilize high-valent metal oxo species. In addition, persistent free radicals naturally bound to the biochar surface promoted singlet oxygen generation during peroxymonosulfate activation.
The catalyst also showed strong practical potential. It maintained more than 85% imidacloprid removal across a wide pH range from 3 to 11, indicating that it could operate under varied wastewater conditions. Common ions such as chloride and sulfate had little influence on performance, consistent with the system's non-radical-dominated mechanism. The catalyst remained active in tap water and several surface water samples, with strong tolerance to realistic water matrices.
Reusability tests further supported the material's stability. After five cycles, imidacloprid removal decreased only slightly, from 96.9% to 91.3%. The spinel crystal structure was retained after reaction, and metal leaching remained low. In a continuous-flow column experiment designed to simulate practical treatment, the catalyst-packed system maintained over 80% imidacloprid removal after 420 minutes of operation.
The system also degraded other neonicotinoid insecticides, including thiamethoxam, clothianidin, dinotefuran, and nitenpyram, suggesting broader applicability beyond imidacloprid. The authors note that while the catalyst showed promising durability, longer continuous operation tests and techno-economic analysis will be needed before full-scale application.
"By using biochar to regulate both catalyst structure and reaction pathway, we can move beyond simple pollutant adsorption and toward efficient catalytic detoxification," the authors said. "This work highlights how biomass-derived carbon materials can be engineered to address emerging water pollution challenges."
The findings offer a rational blueprint for designing biochar hybrid catalysts capable of treating high-strength industrial wastewater contaminated with neonicotinoid insecticides.
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Journal Reference: Dong, X., Ding, Y., Fan, X. et al. Biochar-regulated LDH-derived Co–Mn spinel for non-radical peroxymonosulfate activation: high-efficiency imidacloprid degradation dominated by high-valent metal–oxo species and singlet oxygen. Biochar 8, 109 (2026).
https://doi.org/10.1007/s42773-026-00636-6
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About Biochar
Biochar (e-ISSN: 2524-7867) is the first journal dedicated exclusively to biochar research, spanning agronomy, environmental science, and materials science. It publishes original studies on biochar production, processing, and applications—such as bioenergy, environmental remediation, soil enhancement, climate mitigation, water treatment, and sustainability analysis. The journal serves as an innovative and professional platform for global researchers to share advances in this rapidly expanding field.
